CAMPAIGNERS have welcomed Scottish Labour's historic vote against the renewal of Trident as a significant first step towards reversing the UK party's support for Britain's nuclear deterrent.

Scottish Labour voted emphatically against renewing the Clyde-based missile system after debating the issue for the first time in nearly 20 years.

The decision - backed by just over 70 per cent of the party - becomes Scottish Labour policy and puts it at odds with UK Labour, which supports a new generation of nuclear-armed submarines.

However, it also means UK leader Jeremy Corbyn and Scottish Labour leader Kezia Dugdale both now have a different view on the controversial issue to their party members.

Mr Corbyn backs unilateral disarmament while Ms Dugdale supports it on a multilateral basis.

A spokesman for Mr Corbyn said: “The vote by the Scottish Labour Party conference on Trident renewal and the protection of defence jobs is a clear sign that Labour’s democracy has opened up. Scottish Labour Party members have spoken. That will now feed into the wider UK Labour debate and review of defence policy.”

Shadow Scottish Secretary Ian Murray, who spoke against renewal, said he expected the anti-Trident stance be included in the party's manifesto for next year's Holyrood election.

He said the decision would be an important element in UK Labour's defence review, which is attempting to forge an agreed position on Britain's nuclear deterrent in the face of disagreements between Mr Corbyn and members of his shadow cabinet who favour renewal.

Mr Murray said: "This is part of the process.

"Jeremy has said he wants a democratic and open process. He wants a proper debate, we've done that in Scotland."

Stephen Low, the delegate who moved the motion opposing Trident and a prominent member of the left-wing Campaign for Socialism group, said: "This indicates the direction of travel, I think it will be quite significant.

"Trident is an issue with more salience here than other parts of the UK. I think it will weigh quite heavily."

The Conservatives seized on the vote.

Michael Fallon, the Defence Secretary, said: "This underlines the danger that the Labour leadership poses to our national security.

"We cannot know what threats will emerge over the next 40 years. Renewing the nuclear deterrent is crucial to ensuring we are prepared for the worst of them. It will also guarantee thousands of jobs."

He appealed to "moderate" Labour MPs to maintain their support for a nuclear deterrent.

Scottish Labour debated Trident for the first time since 1998 on the final day of its conference in Perth.

Ms Dugdale did not speak but Jackie Baillie, a key member of her frontbench team was among a number of senior Labour figures who opposed a motion calling for the missiles to be scrapped and "Defence Diversification Agencies" to be created to develop alternative employment for workers who faced losing their jobs.

Adam Ingram, a former armed forced minister who also spoke in favour of Trident renewal, said previous attempts at diversification had "achieved very little".

The strongest opposition came from the GMB union, which represents thousands of defence workers.

Acting secretary Gary Smith told delegates his union "stood tall against a motion that promises Alice in Wonderland politics and pie in the sky jobs".

Among those who backed the motion was Neil Findlay, the MSP who ran Mr Corbyn's leadership campaign in Scotland, and Pat Rafferty, leader of the Unite union in Scotland, which also represents workers whose jobs depend on Trident.

He stressed the importance of jobs and argued a strategy to diversify the defence industry "need not be pie in the sky".

But his backing for the motion opened up a clear split with Unite south of the Border, where leader Len McCluskey last month insisted the union would "not be voting in favour of any anti-Trident resolution" at the Labour conference in Brighton.

His support for retaining Trident played a decisive part in stopping a proposed debate within the party, leading instead to the lengthy defence review.

Trade union support for replacing the deterrent - which is expected to be rubber-stamped by David Cameron's government next Spring - remains a major obstacle to Mr Corbyn's hopes of changing Labour's position.

The 75-minute debate fulfilled a promise by new Scots leader Ms Dugdale to "re-democratise" Scottish Labour.

The motion, drawn up by nine local parties, described Trident as a "mortal threat to humanity's survival" and argued unilateral disarmament would encourage other nuclear powers to ditch their arsenals.

However, it also said jobs must be saved and savings from not commissioning the proposed £167 billion replacement for the weapons system should "sustain a process of defence diversification".

Supporters made a moral case for axing the deterrent, with Mr Low telling delegates: ''This is a life and death decision.

"Let's choose life, let's choose to be the change we want to see in the world, let's cancel Trident renewal.''